As far as its core mechanics go, Defiance is simple at heart. You get to choose among two different races, the humans and the Irathient as well as your preferred gender. Once you've made your choice, you get to choose one of four origins ; the Veteran, the Survivalist, the Machinist, and the Outlaw. As you begin to level you get to upgrade your skill grid with the points you accumulate to build your character. A long the way, you make friends, do raids, and get better gear. What more could you ask for? For now, let's get a little bit more specific about the game's skills and playable characters.
Choosing your race and class
One interesting thing about Defiance is the fact that it's classless and the races don't affect stats. Every player can use any skill and any weapon. The difference between each origin is quite literally, their origin like where they come from. Whether or not that affects the campaign or certain scenarios is still a mystery to me since the small amount of story that was in the beta doesn't change based on the character I chose to play.
I guess the most mechanical difference will be the weapon you start with, since each origin starts with a different weapon. The decision on your starting weapon should be irrelevant because every story quest up to a certain point gives you a different type of weapon, so in the end you'll end up trying everything.
As far as character-choice tips goes, each origin has a different set of outfits that, as far as i'm concerned, can't be changed so really use the character-customization time to really make your avatar how you want it to look, rather than what kind of stats you want it to have, because the game doesn't work that way. Really take advantage of the game's relatively complex and well-done customization options.
Honestly, I kind of like it this way, because I want the game to see me for my skill rather than having another person do more damage then me just because they play the actual "sniper" role.
The Skill Grid
So I mentioned an actual "sniper role." Well, that doesn't exist, but you can build your character through the use of the skill grid which has a decent amount of skills in it to make your character more unique to what you want to do as a player. It's similar to the passive skill tree from Path of Exile but has skills you would've found from games like Mass Effect. So now, that you know the basics, let's get more specific.
Some time in the tutorial, you're given one point to put into your grid which will go towards one of four possible abilities:
That choice is really straightforward. You're even given a tutorial which introduces you to each ability so you can get a feel for what fancies your taste. What's more important is what's around the abilities. This is where you would consider the path you take because it sort of defines your "class." For example, if you opt to go Cloak, there's an ability to the right called "Ambush" which make you do more damage to unsuspecting targets and next to that, a skill that allows you to do more critical damage. I guess you can call that path sort of an "assassin" path.
So, the one thing that Defiance gives to its players is options. Restrictions are very limited and nothing is stopping you from changing your mind about what you want to do. It takes the elements of an MMO; an open world, interaction, PvE and adds elements from an FPS -- choice of class, the ability to swap any time, and little restrictions on player tastes. As far as these mechanics go, Trion World did an excellent job catering to both worlds.